A typical high speed cable includes a center conductor or core surrounded by a tube-like inner dielectric. A shield is disposed outside the inner dielectric for shielding and/or grounding the cable. The shield typically is a tubular metallic braid. However, one or more longitudinal conductive wires have also been used and are commonly called "drain wires." An insulating jacket surrounds the composite cable outside the shield.
Various types of connectors are used to terminate high speed cables. The connectors typically have contacts which are terminated to the center conductor or core of the cable. The connectors also have one form or another of a terminating member for terminating the metallic shield of the high speed cable, usually for grounding purposes. A typical system in such connectors may terminate the metallic shield to the terminating member by soldering or welding. Other systems use crimping procedures to crimp at least a portion of the terminating member securely to the metallic braid.
With the ever-increasing miniaturization of the electronics in various industries, such as in the computer and telecommunications industries, along with the accompanying miniaturization of electrical connectors, considerable problems have been encountered in terminating miniature high speed cables, particularly in terminating the metallic shield of the cable. For instance, the outside diameter of a small coaxial cable may be on the order of 0.090 inch. The outside diameter of the inner dielectric surrounding the conductor/core may be on the order of 0.051 inch, and the diameter of the center conductor/core may be on the order of 0.012 inch. Coaxial cables having even smaller dimensional parameters have been used.
The problems in terminating small coaxial cables often revolve around terminating the metallic shield of the cable. For instance, if soldering methods are used, applying heat (necessary for soldering) in direct proximity to the metallic shield can cause heat damages to the underlying inner dielectric and, in fact, substantially disintegrate or degrade the inner dielectric. If conventional crimp-type terminations are used, typical crimping forces often will crush or deform the inner dielectric surrounding the center conductor/core of the cable. In either case, damage or deformation of the inner dielectric will change the electrical characteristics of the cable.
The above problems are further complicated when the metallic shield of the high speed cable is not terminated to a cylindrical terminating member, but the shield is terminated to a flat terminating member or contact. For instance, an example of terminating the metallic shield or braid of a coaxial cable to a flat ground member is shown in U.S. Pat. No. 5,304,069, dated Apr. 19, 1994 and assigned to the assignee of the present invention. In that patent, the metallic braids of a plurality of coaxial cables are terminated to a ground plate of a high speed signal transmission terminal module. The conductors/cores of the coaxial cables are terminated to signal terminals of the module. Other examples are shown in U.S. Pat. No. 5,711,686, dated Jan. 27, 1998; U.S. Pat. No. 5,716,236, dated Feb. 10, 1998; U.S. Pat. No. 5,718,607, dated Feb. 17, 1998; U.S. Pat. No. 5,725,387, dated Marc. 10, 1998; and U.S. Pat. No. 5,785,555 dated Jul. 28, 1998, all of which are assigned to the assignee of the present invention.
The present invention is directed to further improvements in managing the termination of high speed coaxial cables, including the termination of the metallic shields of a plurality of cables to a terminating member, such as a ground blade.